linux-kernel - Re: Re: [PATCH V3 3/5] misc/pvpanic: add MMIO support

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Date:   Tue, 30 Oct 2018 11:54:03 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     peng.hao2@....com.cn
Cc:     Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Andy Shevchenko <andy@...radead.org>,
        Darren Hart <dvhart@...radead.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Platform Driver <platform-driver-x86@...r.kernel.org>,
        hutao@...fujitsu.com,
        Linux Documentation List <linux-doc@...r.kernel.org>
Subject: Re: Re: [PATCH V3 3/5] misc/pvpanic: add MMIO support

On Tue, Oct 30, 2018 at 5:08 AM <peng.hao2@....com.cn> wrote:
> >On Mon, Oct 29, 2018 at 12:54 PM <peng.hao2@....com.cn> wrote:

> >I would consider it as a bug if on some architectures iounmap() is not
> >able to take a base got from ioport_map().

> I added TYPE_PVPANIC_MMIO in QEMU to the architecture that does not support IOPORT.
>  If some architectures does not support IOPORT, set TYPE_PVPANIC_MMIO in qemu. This setting is reflected in the kernel pvpanic driver
> and does not invoke ioport_map (calling ioremap).  So I think the situation you described above will not happen.

> But I should  resume one check like this to deal with the failure of ioremap/ioport_map.
>      if (base)
>            iounmap(base)

I'm a bit confused, how come that base == NULL when you about to call
iounmap()? Where you would like to put this check?

> The patch of QEMU is still in review.

-- 
With Best Regards,
Andy Shevchenko